假设我们这里有1到5五张bmp图片，那么控制图片切换显示的核心代码可以为：
<script> var i=1; var img = new Array(); img[0] = "1.bmp"; img[1] = "2.bmp"; img[2] = "3.bmp"; img[3] = "4.bmp"; img[4] = "5.bmp"; function playImg(){ i=i+1; var imgs = document.getElementById("img"); imgs.src =img[i]; if(i>=4){ i=1; } } window.onload = function(){ document.getElementById("img").src="1.bmp"; } </script> <img src="" hieght="500">
主要体现了一个图片的切换控制思路，可以用于各种场景，那么下面我们来看一个复杂一些的实现，能够控制滑动和停顿事件等具体的实现图片的滑动切换效果的例子：
var $$ = function (id) { return "string" == typeof id ? document.getElementById(id) : id; }; var Extend = function(destination, source) { for (var property in source) { destination[property] = source[property]; } return destination; } var CurrentStyle = function(element){ return element.currentStyle || document.defaultView.getComputedStyle(element, null); } var Bind = function(object, fun) { var args = Array.prototype.slice.call(arguments).slice(2); return function() { return fun.apply(object, args.concat(Array.prototype.slice.call(arguments))); } } var forEach = function(array, callback, thisObject){ if(array.forEach){ array.forEach(callback, thisObject); }else{ for (var i = 0, len = array.length; i < len; i++) { callback.call(thisObject, array[i], i, array); } } } var Tween = { Quart: { easeOut: function(t,b,c,d){ return -c * ((t=t/d-1)*t*t*t - 1) + b; } }, Back: { easeOut: function(t,b,c,d,s){ if (s == undefined) s = 1.70158; return c*((t=t/d-1)*t*((s+1)*t + s) + 1) + b; } }, Bounce: { easeOut: function(t,b,c,d){ if ((t/=d) < (1/2.75)) { return c*(7.5625*t*t) + b; } else if (t < (2/2.75)) { return c*(7.5625*(t-=(1.5/2.75))*t + .75) + b; } else if (t < (2.5/2.75)) { return c*(7.5625*(t-=(2.25/2.75))*t + .9375) + b; } else { return c*(7.5625*(t-=(2.625/2.75))*t + .984375) + b; } } } } //容器对象,滑动对象,切换数量 var SlideTrans = function(container, slider, count, options) { this._slider = (slider);this.container= (container);//容器对象 this._timer = null;//定时器 this._count = Math.abs(count);//切换数量 this._target = 0;//目标值 this._t = this._b = this._c = 0;//tween参数 this.Index = 0;//当前索引 this.SetOptions(options); this.Auto = !!this.options.Auto; this.Duration = Math.abs(this.options.Duration); this.Time = Math.abs(this.options.Time); this.Pause = Math.abs(this.options.Pause); this.Tween = this.options.Tween; this.onStart = this.options.onStart; this.onFinish = this.options.onFinish; var bVertical = !!this.options.Vertical; this._css = bVertical ? "top" : "left";//方向 //样式设置 var p = CurrentStyle(this._container).position; p == "relative" || p == "absolute" || (this._container.style.position = "relative"); this._container.style.overflow = "hidden"; this._slider.style.position = "absolute"; this.Change = this.options.Change ? this.options.Change : this._slider[bVertical ? "offsetHeight" : "offsetWidth"] / this._count; }; SlideTrans.prototype = { //设置默认属性 SetOptions: function(options) { this.options = {//默认值 Vertical: true,//是否垂直方向（方向不能改） Auto: true,//是否自动 Change: 0,//改变量 Duration: 30,//滑动持续时间 Time: 10,//滑动延时 Pause: 3000,//停顿时间(Auto为true时有效) onStart: function(){},//开始转换时执行 onFinish: function(){},//完成转换时执行 Tween: Tween.Quart.easeOut//tween算子 }; Extend(this.options, options || {}); }, //开始切换 Run: function(index) { //修正index index == undefined && (index = this.Index); index < 0 && (index = this._count - 1) || index >= this._count && (index = 0); //设置参数 this._target = -Math.abs(this.Change) * (this.Index = index); this._t = 0; this._b = parseInt(CurrentStyle(this._slider)[this.options.Vertical ? "top" : "left"]); this._c = this._target - this._b; this.onStart(); this.Move(); }, //移动 Move: function() { clearTimeout(this._timer); //未到达目标继续移动否则进行下一次滑动 if (this._c && this._t < this.Duration) { this.MoveTo(Math.round(this.Tween(this._t++, this._b, this._c, this.Duration))); this._timer = setTimeout(Bind(this, this.Move), this.Time); }else{ this.MoveTo(this._target); this.Auto && (this._timer = setTimeout(Bind(this, this.Next), this.Pause)); } }, //移动到 MoveTo: function(i) { this._slider.style[this._css] = i + "px"; }, //下一个 Next: function() { this.Run(++this.Index); }, //上一个 Previous: function() { this.Run(--this.Index); }, //停止 Stop: function() { clearTimeout(this._timer); this.MoveTo(this._target); } };
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